1
JEE Main 2025 (Online) 2nd April Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Given below are two statements :

Statement (I) : In octahedral complexes, when $\Delta_0<\mathrm{P}$ high spin complexes are formed. When $\Delta_0>P$ low spin complexes are formed.

Statement (II) : In tetrahedral complexes because of $\Delta_t < P$, low spin complexes are rarely formed.

In the light of the above statements, choose the most appropriate answer from the options given below :

A
Both Statement I and Statement II are incorrect
B
Statement I is correct but Statement II is incorrect
C
Statement I is incorrect but Statement II is correct
D
Both Statement I and Statement II are correct
2
JEE Main 2025 (Online) 29th January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Identify the homoleptic complexes with odd number of $d$ electrons in the central metal :

(A) $\left[\mathrm{FeO}_4\right]^{2-}$

(B) $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$

(C) $\left[\mathrm{Fe}(\mathrm{CN})_5 \mathrm{NO}\right]^{2-}$

(D) $\left[\mathrm{CoCl}_4\right]^{2-}$

(E) $\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{O}\right)_3 \mathrm{~F}_3\right]$

Choose the correct answer from the options given below :

A

(C) and (E) only

B

(A), (B) and (D) only

C

(B) and (D) only

D

(A), (C) and (E) only

3
JEE Main 2025 (Online) 29th January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The calculated spin-only magnetic moments of $K_3[Fe(OH)_6]$ and $K_4[Fe(OH)_6]$ respectively are :

A

4.90 and 4.90 B.M.

B

4.90 and 5.92 B.M.

C

5.92 and 4.90 B.M.

D

3.87 and 4.90 B.M.

4
JEE Main 2025 (Online) 29th January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The correct increasing order of stability of the complexes based on $\Delta_0$ value is :

  1. I. $[\text{Mn}(\text{CN})_6]^{3-}$

  2. II. $[\text{Co}(\text{CN})_6]^{4-}$

  3. III. $[\text{Fe}(\text{CN})_6]^{4-}$

  4. IV. $[\text{Fe}(\text{CN})_6]^{3-}$
A

I < II < IV < III

B

IV < III < II < I

C

III < II < IV < I

D

II < III < I < IV

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